Random elastomeric copolyesters

ABSTRACT

This invention relates to random linear copolyesters containing units of terephthalic acid, butane diol, polytetramethylene glycol and dimer acid. The copolymers are elastic materials and can be made into films, fibers and molded products.

TECHNICAL FIELD

This application is a continuation-in-part of my copending applicationSer. No. 40,016 filed May 17, 1979, now abandoned.

The invention described herein relates to random linear copolyestershaving elastomeric properties and to shaped articles prepared from thecopolyesters.

BACKGROUND ART

The prior art discloses elastic polyester resins made of certain orderedblock copolymers as disclosed in U.S. Pat. Nos. 3,023,192 and 3,954,689.Also, elastomeric properties are obtained in copolyesters havingbranched chain compounds in their structure as illustrated in U.S. Pat.No. 4,013,624 and esters that contain side chains as shown in U.S. Pat.No. 3,890,279. The present elastomeric copolyesters are randomcopolymers and different from the prior art materials by being straightchain polymers that contain significant amounts of polyalkylene groupswithin the polymer chain. These materials crystallize rapidly intoopaque solids that are tough and elastic. They have a wide range ofservice temperatures and can be extruded into rods, tubes, hose,filaments and films and they can be injection molded or rotationalmolded into tires and parts having industrial uses.

DETAILED DESCRIPTION

The present copolyesters can be made by the usual procedures for makinghigh molecular weight polyesters, including ester interchange,esterification and polycondensation or a combination of these processes.They are essentially random straight chain polymers without any dangling(i.e. pendant) groups attached either to the acid residues or the glycolresidues and are copolyesters in that they contain units of differentpolyester-forming materials within the polymer chains.

It is an object of this invention to provide a synthetic polyestermaterial capable of being formed into filaments, films and moldedarticles which possess high elastic recovery.

This objective is accomplished by providing elastomeric, random, linearcopolyesters having intrinsic viscosities ranging from about 0.6 toabout 1.0 as determined in a 60/40 by volume mixed solvent system ofphenol and tetrachloroethane at 30° C. and melting points ranging fromabout 180° C. to about 220° C., said copolyesters comprising .[.thepolymeric reaction product of a mixture of reactants.]. .Iadd.a mixtureof units in the polymer chain .Iaddend.consisting of the .Iadd.polymericreaction product from .Iaddend.

(a) terephthalic acid or a lower C₁ -C₄ dialkyl ester thereof,

(b) dimer acid,

(c) a poly(tetramethylene oxide)glycol having a molecular weight rangingfrom about 1000 to about 2000 and

(d) 1,4-butane diol

in which mixture the amount of terephthalic acid or lower C₁ -C₄ dialkylester thereof ranges from about 99.9 to about 85.0 mole percent and theamount of dimer acid ranges from about 0.1 to about 15.0 mole percent,said percentages being based on the total number of moles of said acidconstituents or reactive equivalents thereof in said mixture and inwhich mixture the amount of poly(tetramethylene oxide)glycol ranges fromabout 2.0 to about 12.0 mole percent and the amount of 1,4-butane diolranges from about 98.0 to about 88.0 mole percent, plus a molar excessof said 1,4-butane diol ranging from about 5.0 to 120.0 percent, saidpercentages being based on the total number of moles of said glycolconstituents, less the molar excess of the 1,4-butane diol, in saidmixture. A more preferred range for the acid constitutents or theirreactive equivalents in the above-defined reaction mixture is from about99.5 to about 86.8 mole percent for the terephthalic acid or lower C₁-C₄ dialkyl ester thereof and from about 0.5 to about 13.2 mole percentof the dimer acid. .Iadd.The terephthalic acid, the lower C₁ -C₄ dialkylester thereof, and the dimer acid are referred to collectively as"acid-derived units" in the polymer chain, whereas thepoly(tetramethylene oxide) glycol and the 1,4-butane diol are referredto collectively as "glycol-derived units" in the polymer chain..Iaddend..

As noted hereinabove a molar excess of the 1,4-butane diol, ranging fromabout 5.0 to about 120 percent of the number of moles of this diolneeded to react with the moles of acid constituents or their reactiveequivalents in the mixture, is employed. This excess is employed inorder to insure reasonable rates of reaction between the glycolconstituents and the acid constituents or the reactive equivalentsthereof. As a result of the use of this excess of the 1,4-butane diol,the molar ratio of all the glycol constituents to all of the acidconstituents or their reactive equivalents in the mixture will rangefrom about 1.05:1.0 to about 2.20:1.0.

The dimer acid useful in preparing the copolyesters constituting thepresent invention is itself prepared from an unsaturated fatty acidcontaining 18 carbon atoms such as linoleic and linolenic acid or themonohydric alcohol esters thereof. The actual preparation and structureof dimerized C₁₈ fatty acids are described in J.A.C.S. 66,84 (1944) andU.S. Pat. No. 2,347,562, both of which are incorporated herein byreference. Several different grades of dimer acid are available fromcommercial sources and these differ from each other primarily in theamount of the monobasic and trimer acids fractions and the degree ofunsaturation. It is preferred, for purposes of this invention, the dimeracid be substantially free of the monobasic and trimer acids fractionsand essentially completely saturated. Two different grades of dimeracid, which are useful in preparing the copolyesters herein describedand meet the above requirements and which are available from EmeryIndustries, Inc. under the trade name Empol, are Empol 1010 and Empol1014. Empol 1010 dimer acid is reported as typically containing 97%dimer acid, 3% trimer acid and essentially no monobasic acids andextremely low unsaturation and Empol 1014 is reported as typicallycontaining 95%, 4% and 1% of dimer, trimer and monobasic acidsrespectively.

The elastomeric, random, linear copolyesters of the present inventionand derived from the reaction mixtures defined hereinabove are preparedby conventional and well-known techniques used in preparing highmolecular weight linear polyesters. In general, the copolyesters areprepared by first subjecting the mixture of reactants to elevatedtemperatures under an inert gas atmosphere at atmospheric orsuperatmospheric pressures in the presence of a catalyst to promote theesterification or combined transesterification/esterification reactions,depending on the nature of the starting materials, between the glycolconstituents and the acid constituents or reactive equivalents thereofcomprising said mixtures. Known catalysts useful in promoting thesereactions include the zinc, magnesium, calcium, manganese, lead andtitanium containing compounds. The amount of catalyst used can be variedover a wide range. Generally the amount used will be in the range offrom about 0.005 to about 0.03 percent by weight based on the amount ofreactants used. The temperatures normally employed to affect theesterification or combined transesterification/esterification reactionswill generally range from about 150° C. to about 240° C. and preferablyfrom about 190° C. to 230° C.

Following completion of the esterification or combinedtransesterification/esterification reaction, the low molecular weightoligomer product produced thereby is subjected to polycondensation. Thepolycondensation reaction will be carried out at temperatures rangingfrom about 220° C. to about 280° C. and preferably from about 240° C. toabout 270° C. at pressures below 15 and preferably below 1 millimeter ofmercury (mmHG) pressure in the presence of a polycondensation catalystsuch as the known antimony, titanium, iron, zinc, cobalt, lead,manganese, niobium or germanium catalysts.

The following examples illustrate the preparation of the copolymers ofthe invention and set out some of their desirable properties. In theseexamples, parts or percentages are by weight unless otherwise specified.

EXAMPLE 1

An elastomeric, random linear copolyester was prepared from a mixture ofreactants consisting of 11.3 pounds of dimethyl terephthalate, 6.59pounds of 1,4-butane diol (inclusive of a 33% molar excess), and 6pounds of poly(tetramethylene oxide)glycol having a molecular weight ofabout 1000 (Polymeg 1000) were charged into a 25 pound reactor andreacted in the presence of 60 ppm of titanium, based on the weight ofthe charge, as catalyst at temperatures running from 174° C. to 215°C.After all the by-product methanol was distilled out, 1.6 pounds of dimeracid was added. The resultant mixture was further reacted at 215° C. forone hour. The pressure in the reactor was slowly reduced while thetemperature was raised to 250° C. The polymerization was carried out at254° C. and 0.5 millimeters of mercury pressure. Three hours later, thecopolyester product was discharged. It had an intrinsic viscosity of0.886. It was a white, tough, rubbery solid. It was ground and used forinjection molding tests. The melting point was 206° C. (Intrinsicviscosity in the example of this specification was determined in a 60/40phenol/tetrachloroethane mixed solvent at 30.0° C.)

EXAMPLE II

The same procedure as employed in Example I was followed to produce acopolyester of the invention except that the concentration of reactantsin the reaction mixture were as follows:

Dimethyl terephthalate=10.3 lbs.

Butane Diol=6.21 lbs. (inclusive of a 33% molar excess)

Polymeg 1000=6 lbs.

Dimer Acid=2.6 lbs.

The final intrinsic viscosity of the copolyester was 0.874 and themelting point was 190° C.

EXAMPLE III

The procedure of Example I was followed to produce a copolyester from amixture of reactants of follows:

Dimethyl terephthalate=9 lbs.

Butane Diol=5.7 lbs. (inclusive of a 33% molar excess)

Polymeg 1000=6 lbs.

Dimer Acid=4 lbs.

The copolyester product had an intrinsic viscosity of 0.869 and amelting point of 182° C.

EXAMPLE IV

The polymers prepared in the above examples were injection molded intoASTM test pieces. The test results are listed below:

    ______________________________________                                                             Stress   Tensile Set                                                                           Hardness                                Tensile     Elong.   @ 100%   @ 100%  Shore                                   Example                                                                              @ Break  @ Break  Elong. Elong.  A    D                                ______________________________________                                        I      3068 psi 480%     1789 psi                                                                             47%     93   46                                      @ 480    (NB)*                                                                Elong.                                                                 II     2638 psi 515%     1592 psi                                                                             44%     93   45                                      @ 515%   (NB)*                                                                Elong.                                                                 III    1700 psi 420%     1145 psi                                                                             37%     89   34                               ______________________________________                                         *NB = No Break                                                           

Physical properties of films produced from copolyesters of thisinvention, by means of a flat die process, are set forth in Examples V,VI and VII below. In addition, the mole percent of each of the reactantsin the reaction mixture used to prepare the copolyester employed in thefilms tested is also indicated. With respect to the mole percentagesindicated for the two glycol constituents, the value listed for the1,4-butane diol component is exclusive of the approximately 33 percentexcess of this diol present in the reaction mixtures employed to producethe various copolyesters.

EXAMPLE V

    ______________________________________                                        99.5/0.5-98/2 Terephthalate/Dimerate - Butane Diol/Polymeg                    1.1 mil thick  Heat Seal T = 440° F.                                   Tensile at Break                                                                             Break Elongation                                               ______________________________________                                        MD        10,700 psi                                                                             360%                                                       T          6,500 psi                                                                             520%                                                       ______________________________________                                    

EXAMPLE VI

    ______________________________________                                        95.4/4.6-90.1/9.9 Terephthalate/Dimer Acid - Butane Diol/                     Polymeg                                                                       1.4 mil thick Heat Seal T = 415° F.                                    Tensile at break                                                                            Break Elongation                                                ______________________________________                                        MD       6,000 psi                                                                              580%                                                        T        4,600 psi                                                                              660%                                                        ______________________________________                                    

EXAMPLE VII

    ______________________________________                                        86.8/13.2-88.7/11.3 Terephthalate/Dimerate - Butane Diol/                     Polymeg                                                                       101.5 mil thick                                                                             Heat Seal T = 375° F.                                    Tensile at break                                                                            Break Elongation                                                ______________________________________                                        MD       2,500 psi                                                                              740%                                                        T        2,200 psi                                                                              710%                                                        ______________________________________                                         MD = Machine Direction                                                        T = Transverse Direction                                                 

Film of copolyesters of the invention are useful in a number ofpackaging applications. They can be used as protective films to packagetextiles, tires, tubes and other rubber products. Film having highelongation will be useful for packaging fresh red meats and other foodproducts.

If desired, the properties of these copolyesters can be modifiedsomewhat by the incorporation of plasticizers, lubricants, fillers,pigmenting agents and stabilizers.

As set out before, the copolyesters will have melting points in therange from about 180° C. to about 220° C. This broad range of meltingpoints allows for a wide range of service temperatures for thesecopolyesters.

The expression "melting point" of the copolyesters as used in thisspecification is the minimum temperature at which a sample of polymerleaves a wet molten trail as it is drawn across the surface of theheated block of aluminum. Sometimes this temperature is called a polymerstick temperature.

Stabilizers are added to the copolyesters to provide additionalstability against the deteriorating effects of heat or light. Phenols,amines, oximes, and salts of metals are suitable stabilizers.

The elastomeric copolyesters of this invention are characterized by highstrength and high stretch modulus. These copolymers may be spun readilyinto yarns and into low denier filaments.

Yarns prepared from the copolyesters of this invention will find manyuses in the textile and related fields. They may be uses in themanufacture of two-way stretch, woven and knitted articles. Also, theymay find use in non-woven fabrics and as bonding materials in paper andin the non-woven fabrics.

While certain representative embodiments and details have been shown forthe purpose of illustrating the invention, it will be apparent to thoseskilled in this art that various changes and modifications may be madetherein without departing from the spirit or scope of the invention.

.[.I claim:.]..Iadd.What is claimed is: .Iaddend.
 1. As compositions ofmatter, elastomeric, random, linear copolyesters having intrinsicviscosities ranging from about 0.6 to about 1.0 as determined in a 60/40by volume mixed solvent system of phenol and tetrachloroethane at 30°C., and melting points ranging from about 180° C. to about 220° C., saidcopolyester comprising .[.the polymeric reaction product of.]. a mixtureof .[.reactants.]. .Iadd.units in the polymer chain .Iaddend.consistingof .Iadd.the polymeric reaction product from .Iaddend.(a) terephthalicacid or a lower C₁ -C₄ dialkyl ester thereof, (b) dimer acid, (c) apoly(tetramethylene oxide)glycol having a molecular weight ranging fromabout 1000 to about 2000 and (d) 1,4-butane diolin which mixture theamount of terephthalic acid or lower C₁ -C₄ dialkyl ester thereof rangesfrom about 99.9 to about 85.0 mole percent and the amount of dimer acidranges from about 0.1 to about 15.0 mole percent, said percentages beingbased on the total number of moles of said acid constituents or reactiveequivalents thereof in said mixture and in which mixture the amount ofpoly(tetramethylene oxide)glycol ranges from about 2.0 to 12.0 molepercent and the amount of 1,4-butane diol ranges from about 98.0 toabout 88.0 mole percent, plus a molar excess of said 1,4-butane diolranging from about 5.0 to about 120 percent, said mole percentages beingbased on the total number of moles of said glycols, less the molarexcess of the 1,4-butane diol, in said mixture.
 2. The copolyesters ofclaim 1 .[.comprising the polymeric reaction product of the mixture ofreactants in which mixture.]. .Iadd.wherein the units in the polymerchain from .Iaddend.the terephthalic acid or lower C₁ -C₄ dialkyl esterthereof ranges from about 99.5 to about 86.8 mole percent and the dimeracid ranges from about 0.5 to 13.2 mole percent, said mole percentagesbeing based on the total number of moles of said acid constituents orreactive equivalents thereof in said mixture.
 3. The copolyesters ofclaim 1 comprised of the reaction product of .[.a mixture of.].reactants consisting of dimethyl terephthalate, dimer acid,poly(tetramethylene oxide)glycol having a molecular weight of about 1000and 1,4-butane diol.
 4. A copolyester according to claim 1 in the formof a film ranging in thickness from about 1.1 to about 1.5 mils, saidfilm having a tensile strength of from about 10,700 to about.[.2,5000.]. .Iadd.2,500 .Iaddend.per square inch and an elongation atbreak ranging from about 360 to about 740 percent.
 5. A copolyesteraccording to claim 1 in the form of a molded product.
 6. A copolyesteraccording to claim 1 in the form of a filament. .Iadd.
 7. A copolyesterconsisting essentially of (A) about 99.9 to 85% units from dimethylterephthalate and (B) about 0.1 to 15% units of dimer acid, wherein (A)and (B) are based on mols of total acid-derived units, and (C) about 2to 12% units from polytetramethylene glycol with a molecular weight ofabout 1,000 to 2,000 and (D) about 98 to 88% units from 1,4-butane diol,wherein (C) and (D) are based on mols of total glycol-derived units,said copolyester having an intrinsic viscosity of about 0.6 to 1.0 basedupon a determination in a 60/40 phenol tetrachlorethane mixed solvent at30.0° C. and a melting point of about 180° C. to 220° C. .Iaddend..Iadd.8. A copolyester consisting essentially of (A) about 99.9 to 85% unitsfrom dimethyl terephthalate and (B) about 0.1 to 15% units of dimeracid, wherein (A) and (B) are based on mols of total acid-derived units,and (C) about 2 to 12% units from polytetramethylene glycol with amolecular weight of about 1,000 to 2,000 and (D) about 98 to 88% unitsfrom 1,4-butane diol, wherein (C) and (D) are based on mols of totalglycol-derived units, which is made by reacting said dimethylterephthalate, said 1,4-butane diol and said polytetramethylene glycolin the presence of a transesterification catalyst until substantiallyall the methanol formed from said reaction is distilled off, thereafterreacting the resultant product with said dimer acid, and continuing thereaction to form a copolyester having an intrinsic viscosity of about0.6 to 1.0 based upon a determination in a 60/40 phenol tetrachlorethanemixed solvent at 30.0° C., and a melting point of about 180° C. to 220°C. .Iaddend. .Iadd.
 9. The copolyester of claim 8 wherein thepolytetramethylene glycol has a molecular weight of about 1,000..Iaddend..Iadd.
 10. The copolyester of claims 1, 3, 7, 8, or 9 havingintrinsic viscosities of at least about 0.869. .Iaddend.